Research in this laboratory focuses on the unique mechanisms of activation of T and B lymphocytes and how these cells interrelate in cellular immune responses. Once triggered, these lymphocytes proliferate and produce biologically active lymphokines which may act on macrophages to initiate migration (chemitactic factor) and enzyme production (macrophage activation factor). Whether these and other signals for macrophage activation are translated via alterations in cyclic AMP and GMP levels is being investigated. In addition to lymphokines which trigger macrophage function, activated lymphocytes also release a soluble factor(s) which stimulates fibroblast proliferation and modulates collagen synthesis. Activated macrophages can also influence fibroblast function. By these mechanisms the immune system may control connective tissue metabolism in inflammatory lesions.